Base plate for sewing machines



May 22, 1956 A. PAGNl 2,746,411

BASE PLATE FOR SEWING MACHINES Filed April 14, 1953 IN V EN TOR.

United States Patent BASE PLATE FOR SEWING MACHINES Alessandro Pagni, Milan, Italy, assignor to Vittorio Necchi Societa per Azioni, Pavia, Italy Application April 14, 1953, Serial No. 348,636 Claims priority, application Italy April 28, 1952 1 Claim. (Cl. 112-260) Sewing machine structures always exhibit a resting plane for work, called the base. While the lower portion of said base carries the connections for the mechanical members forming the stitch, the four end and peripheral sides thereof are constituted by smooth vertical walls.

The present invention solves some problems inherent with the functionality of said vertical walls.

The conventional technique generally obtained the bases of sewing machines with casting processes and said vertical walls remained non-worked.

Later on, chiefly to meet the known requirements of interchangeability of modern constructions of series manufacture and owing to the approximation in the keeping of dimensions, more accurate mechanical working was introduced.

The base thus worked also at the borders solved also problems of reference, of working and of controlling, which now could start from the very borders of the base.

The present invention solves successive problems born from the application of this technique.

In particular, the accurate working to dimension of said contour could also comply with the conditions of an accurate adjustment between the base and the fixing-in walls of the socket, table or other support which said bases have to receive and hold in position.

In the manufacture of said supports however wood is used in general and a rather heavy inconvenience is that this material is not always free from variations of dimensions due to even small restrictions or elongations, which cannot be completely overcome by the treatments used with this material. On the other hand, to substitute metal for wood would certainly not always represent a solution, wood being-with few exceptionsalways cheaper and less heavy and, at the same time, it would be obnoxious to leave much play between the two pieces coupled with each other, which would constitute an inlet for dust or foreign bodies.

The present invention eliminates the aforesaid inconveniences by interposing between the vertical walls of the wood and those of the base a conveniently shaped sectional piece of plastic. Said plastic piece acts as an elastic pad between the two materials, adapts itself with accuracy, tolerating also the small relative variations of dimensions of the two joined pieces and establishes if required a seal adapted to prevent any introduction of dust into the mechanisms accommodated under the base and already subjected to various other causes of wear.

Moreover, during shipping, transport and working for repair of the sewing machine and during inspection of the mechanisms accommodated under the base by the operator, often the machine has to be extracted from the aforesaid fixing-in seats and the vertical walls of the base 2,746,41 l Patented May 22, 1956 then were subjected to impacts damaging their surface finish and constituted a possible danger of bruising and wounding for hands.

With the present invention, also these inconveniences can be obviated by fixing the small border band of plastics directly on the vertical walls of the base.

The fastening system of said border band may be also in a characteristic manner by means of fixing-in said band into the very borders of the sewing machine shaped conveniently and securing said fixing-in with the tension of a wire running inside said band and adjustable and fixable by means of two screws.

The following descriptions and the drawings illustrate merely by way of example one means of embodiment of the invention, which may also be shaped differently in its parts without departing from the scope of the principle of the invention.

Figure 1 shows a base surrounded by a border band of plastics, seen from below.

Figure 2 shows on larger scale a section of the fixingin of the band in the external borders of the base of the sewing machine.

Figure 3 shows a detail of the fastening tensioning of the wire in larger scale;

1 is the base of the sewing machine, 2 is the border band of plastics that surrounds the entire perimeter of the base 1 and terminates at the ends 3 of a recess 10 in said perimeter in order to allow sliding of the needle plate. 4 is the metal wire that can slide inside 2 over its whole length. 5 are the two fastening screws holding the wire 4 in tension by pressing it against the base 1. 6 is the groove provided for the fixing-in into the external borders of 1. 7 is the part of plastic band that is fixed-in at 6. The faces 8 are inclined as in the drawing in order to ensure perfect adherence between said faces and thevertical walls of the base when the metal wire 4 is tensioned and secured to the two screws 5.

Application as appears clearly from the drawings, is effected in the following Way.

The border band 2 containing the wire 4, is applied to the borders of 1, taking care that 7 be fixed-in at 6 along the whole periphery of 1 as far as the ends 3. I

Then the two free ends of the wire 4 at 3 are tensioned and fixed by means of the two screws 5 tightened thoroughly.

What I claim is:

A sewing machine supporting structure comprising a base plate having a recess at one side thereof for a needle plate, said base. plate having a groove extending throughout the periphery thereof, a strip of yielding material having a'tongue positioned in said groove, said strip covering the outside periphery of said base plate, a wire located within said strip having a length exceeding the length of said strip to provide a free end of said wire at each end of said strip and means located at the sides of said recess for fastening said free ends of said wire to said base plate and thereby secure said strip to saidbase plate.

References Cited in the file of this patent UNITED STATES PATENTS Germany Apr. 17, 1936 

